During the study, daily asthma symptoms, peak expiratory flow, rescue and background medication use, and compliance with the study medication will be recorded via subject diary. Treatment-Emergent Adverse Events (TEAEs) will be assessed and recorded throughout the study. A full physical exam, routine hematology, blood chemistry, spirometry, vital signs measurement, 12-lead ECG and pregnancy testing will be performed before enrollment and at end of study. Furthermore on Day 1 and 14 of each treatment period, serial spirometry, 12-lead ECGs, BP, and serum potassium and glucose will also be measured at the study center up to 12 hours post-dosing.